Updated at 4:45 p.m.: Revised to reflect that Garland, Rowlett and Plano's systems have been fixed.

Several cities in North Texas — including Plano, Rowlett and Garland — said Monday that some cellphone users were having trouble connecting to 911 dispatchers for police and fire help.

By 4 p.m. on Monday, the systems had been fixed in all three cities.

Rowlett officials realized around 10 p.m. Sunday that their 911 lines weren't working properly, police Lt. David Nabors said. They soon learned that there was an issue with a fiber-optic line, operated by Frontier Communications, that runs between Denton and Lewisville and allows dispatchers to receive 911 calls.

Rowlett rerouted its calls to Garland's dispatchers, who also started having problems around 5 a.m.

Garland police said their system was back to normal just before 3 p.m., and Rowlett police said their system was fixed a few minutes later.

We are pleased to announce the problems with 911 calls regarding mobile phones have been resolved. All emergency systems are back to normal.